I thought I'd write a guide for people who don't know how to format their NTFS Flash Drives to HFS+ or FAT32 in Disk Utility. I think it would be a good idea to sticky this to cut down the amount of threads about this and so that the replies could simply link to this guide. Reply and tell me what you think of the guide as this is my first one. So, you've just plugged in the USB drive that you've been using with your PC for ages, right? You drag a file into the drive, and, oh no! This means your drive is formatted with NTFS, a file system that works only with Microsoft Windows. You will need to reformat it to work with a Mac only, or with Mac & Windows. This guide will show you how. WARNING: Formatting your drive will erase everything on it. Back up all of the files on the drive before erasing it. First, find Disk Utility. If you have Mac OS X Tiger, you can do a Spotlight search by clicking the blue magnifying glass symbol in the top right hand corner of the screen. If you don't have Tiger, you can find Disk Utility in /Applications/Utilities. Earlier versions of Disk Utility differ, but the method should be basically the same. Open Disk Utility and you will see a screen that looks something like this. Now, find your USB drive in the left hand menu, and click on it. Now, click on the 'Erase' tab. Opening the 'Volume Format' drop-down menu, you can see that we have quite a few options. Choosing 'Mac OS Extended (Journaled)' (also known as HFS+) will make your drive compatible only with a Mac, and a Windows computer will not even be able to see what is on it. Choosing 'MS-DOS File System' (also known as FAT32) will make your drive completely compatible with both a Mac and Windows computer, but you cannot make a file any larger than 4GB. Whichever option you choose, you are now ready to format your drive. Click the 'Erase' button and you will see a warning like this. Click 'Erase' on the warning to continue. You will now see a small progress bar appear near the bottom of Disk Utility. When it is full, your drive is formatted, and is now compatible with your Mac. Congratulations, you've just formatted your USB drive using Apple's Disk Utility software!